Suction collection systems are commonly employed to drain extraneous fluids, blood, fibrin, blood clots (hematomas), secretions, gastro-intestinal contents and the like from the body. In some postoperative surgical drain applications, suction at levels of 120 mm Hg. to 250 mm Hg. or more may be used. In addition to fluid evacuation, the higher levels of suction are used to provide better fibrin and hematoma or viscous exudate evacuation, to provide internal wound compression, and to promote complete tissue approximation and obliteration of dead space in the surgical wound. The higher levels of suction help prevent clogging of drain systems (a problem commonly associated with low suction wearable devices), and, as stated, help accelerate healing by providing better tissue approximation through internal compression that eliminates dead spaces.
Suction/collection systems are also commonly employed to drain fluids from the esophogus, stomach, and intestinal tract through tubes inserted through either the nasal or oral passages. Suction collection systems are also commonly used for the collection of suctioned materials from lung cavity through thoracic catheters. A more detailed discussion of each of these applications follows.
Closed Wound Suction (C.W.S.) drainage and collection is commonly employed for postoperative drainage of the surgical wound. In C.W.S. drainage the surgeon places a catheter with drain openings (eyes) in the wound site or sites to be drained at the end of the surgical procedure, and secures the drainage catheter to the skin, usually with a suture, at the exit site so that an air tight seal is created in the wound, i.e., a closed wound is created. The proximal end of the drainage catheter is then connected to the suction source. The suction source may be a self-contained wearable, portable device such as described in U.S. Pat. Nos. 3,115,138 (McElvenny) or 4,112,949 (Rosenthal), among others, or provided by a wall suction outlet with or without a suction regulator which receives its vacuum from a central vacuum system in the building. The suction source may also be connected to an A.C. electrical pump such as the Gomco pump. The wall or electric pump systems utilize separate glass or plastic collection bottles or cannisters for collection of the fluids and other materials. These bottles are placed between the suction source and wound catheter and act as a trap to collect the suctioned materials.
Wearable, portable, self-contained disposable suction/collection devices are very popular for C.W.S. applications because they can travel with the patient during patient transport and whenever the patient is away from the bedside such as for radiation therapy or physical therapy. These devices also permit early patient ambulation which assists in early recovery and discharge. These units employ internal metal springs, compressable elastic bulbs, or inflatable latex balloons as the source of suction. Suction levels delivered by these devices generally ranges from 25 mm. Hg. to about 100 mm. Hg., depending on model and manufacturer. Such devices do not provide either a precise level of suction, nor do they deliver a constant level of suction, as the suction level normally drops substantially during the fill cycle.
A number of problems are experienced with these portable, wearable, self-contained suction/collection devices. For example, clogging of the drain eyes and drain system lumen is a frequent problem in certain common applications. This clogging is due to the low and inconsistent levels of suction delivered. Ineffective drainage results from clogged systems and this can lead to infection of the operative site as undrained fluid accumulations and hematomas provide an ideal medium for bacterial proliferation. Further, retrograde infection can result from contamination of the collection reservoir. These collection reservoirs usually become contaminated within 24 to 48 hours with exogenous bacteria because of the frequent opening and reactivation required in attempting to maintain the highest levels of suction. The exogenous bacteria can then proliferate inside the reservoir and migrate through the system into the wound site. In addition, the lack of sufficiently high and constant suction provided may result in less than optimal wound drainage, internal wound compression, elimination of dead space, and tissue approximation. Thus, low suction levels of a declining type as supplied by these units can potentiate infection and retard healing. Because of these problems with the self-contained suction devices, many surgeons employ either wall suction of Gomco type A.C. suction pumps. Wall systems provide suction levels ranging from low levels of 1 to 80 mm Hg. up to maximum levels of 200 mm. Hg. or more.
The Gomco type A.C. vacuum pump systems provide suction levels ranging up to 400 to 500 mm. Hg. or more. The wall suction systems are used more frequently in the hospitals for C.W.S. drainage because wall suction is readily available in most patient rooms in modern hospitals.
There are a number of important advantages of the wall and electrical pump systems over the wearable, self-contained devices. For example, the suction level provided is variable over a range from low to high. Further, the suction level can be set at any desired level, and can be increased to a higher level if problems with clogging occur. In addition, the suction can be temporarily set lower if excessive bleeding should occur. Further, such systems can deliver sufficiently high suction at a relatively constant level to drain effectively without clogging by fibrin or hematoma. The higher suction levels afforded by such systems can provide sufficient internal wound compression to eliminate dead spaces, and can maximize tissue approximation for optimal, rapid wound healing by primary intention without complications such as infection or delayed healing.
The major problem with these systems is that the suction must be disconnected every time a patient is transported, such as during transport from recovery to the patient's room, or when the patient goes for physical or radiation therapy. Further, the patient cannot become ambulatory when the wound is still draining. As mentioned above, early ambulation is highly desirable as it contributes to earlier recovery and discharge. On the other hand, it is undesirable to break the suction because drains without suction or with low levels of suction are prone to poor or ineffective drainage, or complete stoppage by clogging. Breaking the suction system also exposes the system to contamination by exogenous bacteria and retrograde infection.
Wall suction systems are also very imprecise and inaccurate. One hospital system tested with a gauge precalibrated with a mercury manometer delivered 150% higher actual suction levels than the set point on the regulator. Specifically, at a setting of 80 mm. Hg., the system delivered an average of 125 mm. Hg., at a 120 mm. Hg. set point delivered an average of 191 mm. Hg., and at a 200 mm. Hg. delivered 331 mm. Hg. In other hospitals with limited central vacuum capability, the suction level delivered by wall suction can be substantially less than is indicated on the regulator, a condition that will be magnified at peak demand periods. Thus the physician generally cannot know the actual level of suction being delivered with wall systems, because this level varies from regulator to regulator in a hospital, and from hospital to hospital
Pleural (chest) drainage is a special type of C.W.S. drainage. Since the lung will collapse if atmospheric pressure is allowed to enter the pleural cavity such as through a post operative drainage catheter, a special suction draining system employing a water seal located between the catheter and the suction source is most commonly used. The water/seal collection unit is attached to an A.C. electrical pump or to wall suction at low levels of suction.
Sump suction systems are those systems that provide one or more air inlet channels (lumens) in the tube or catheter system, combined with a suction lumen to be connected to a suction source such as wall suction or an A.C. Gomco type pump. The objective of the sump system is to provide a suction release in event that soft tissue seals off the openings in the catheter or tube tip. Air enters the system, and prevents tissue from invaginating into the eyes with resultant tissue damage. Sump suction drain tubes are most commonly used in nasogastric tubes to drain the stomach. Surgical sump drains are mainly used in abdominal procedures.
One of the major problems with these systems is that they must be broken whenever the patient is being transported or moved, as described with regard to wall and machine systems for C.W.S. drainage. These systems then may become clogged and require irrigation which may or may not clear the catheter. Portable, self-contained suction devices cannot be employed as they simply suck in air from the air inlet and/or volumes of air and exudate suctioned are too great.
A special portable suction pump for pleural drainage for field emergency or for use while a patient is being transported to the hospital is described in U.S. Pat. No. 4,306,558 (Kurtz). This system controls vacuum through a bleed valve which requires continuous motor operation and battery draw. A manual pump is included so that the unit is still operable in event the battery power or electrical pump failure.